1. Technical Field
The invention relates generally to multi-voltage island/core architectures, and more particularly, to a driver for a multi-voltage island/core architecture.
2. Background Art
As complementary metal oxide semiconductor (CMOS) technologies are scaled, total chip power dissipation is becoming high and is limiting the performance of an integrated circuit chip. Simultaneously, static (leakage) power dissipation is becoming a significant component of total chip power dissipation. A multi-voltage island/core architecture is a solution to the power dissipations. A multi-voltage island/core architecture is designed to independently adjust the voltage supply (Vdd) of each function block in an integrated circuit chip so that the total and the static power dissipation is minimized for each function block while still meeting the chip performance requirements. Each function block with a voltage supply may be referred to as a voltage island/core. One problem is how to build a driver between two voltage islands/cores that have different Vdd.
A CMOS inverter may be used as a driver between two voltage islands/cores. However, a CMOS inverter also has the problem of leakage, i.e., subthreshold leakage current. Raising threshold voltage of a CMOS inverter may reduce leakage and may increase noise margin, but may also result in serious loss in performance, for example, prolonged rise time. As such, the choice of the threshold voltage has to represent a trade-off between subthreshold leakage current and performance.
Based on the above, there is a need in the art for a driver for a multi-voltage island/core architecture that addresses, among others, the above described problems.